title: Novel method for selection of antimicrobial peptides from a phage display library by use of bacterial magnetic particles.
abstract: Antimicrobial peptides were isolated from a phage display peptide library using bacterial magnetic particles (BacMPs) as a solid support. The BacMPs obtained from "Magnetospirillum magneticum" strain AMB-1 consist of pure magnetite (50 to 100 nm in size) and are covered with a lipid bilayer membrane derived from the invagination of the inner membrane. BacMPs are easily purified from a culture of magnetotactic bacteria by magnetic separation. Approximately 4 x 10(10) PFU of the library phage (complexity, 2.7 x 10(9)) was reacted with BacMPs. The elution of bound phages from BacMPs was performed by disrupting its membrane with phospholipase D treatment. Six candidate peptides, which were highly cationic and could bind onto the BacMP membrane, were obtained. They exhibited antimicrobial activity against Bacillus subtilis but not against Escherichia coli and Saccharomyces cerevisiae. The amino acid substitution of the selected peptide, KPQQHNRPLRHK (peptide 6-7), to enhance the hydrophobicity resulted in obvious antimicrobial activity against all test microorganisms. The present study shows for the first time that a magnetic selection of antimicrobial peptides from the phage display peptide library was successfully achieved by targeting the actual bacterial inner membrane. This BacMP-based method could be a promising approach for a high-throughput screening of antimicrobial peptides targeting a wide range of species.
authors.affiliation: Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tanaka
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Kokuryu
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D019943:Amino Acid Substitution; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects*; D057927:Hydrophobic and Hydrophilic Interactions; D008280:Magnetics; D042201:Magnetospirillum; D015388:Organelles / Q000378:metabolism; D019151:Peptide Library; D012441:Saccharomyces cerevisiae / Q000187:drug effects*
chemical_list: D023181:Antimicrobial Cationic Peptides; D019151:Peptide Library